SINA's January 2013 57.50-strike call was popular on Friday

Calls were in heavy rotation on SINA Corp (NASDAQ:SINA - 54.75) on Friday, with the contracts trading at nearly three times their average daily pace. Of the roughly 29,000 calls that changed hands on the day, 5,784 crossed at SINA's January 2013 57.50 strike. A healthy portion of these went off at the ask price, and open interest added more than 2,600 contracts over the weekend -- hinting at the initiation of new positions.

By buying these out-of-the-money calls to open for a volume-weighted average price (VWAP) of $0.79, traders need SINA to finish above $58.29 (the strike plus the VWAP) by week's end, when front-month options expire. This breakeven mark is a 6.5% premium to the stock's current perch.

Considering SINA is up about 9% in 2013, it's no surprise that option players have been scooping up calls over puts with some rapidity in recent weeks. At the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX), traders have bought to open 258 calls for every 100 puts during the past 10 sessions. The resultant call/put volume ratio of 2.58 ranks higher than 87% of other such readings taken in the last year, pointing to a healthier-than-usual appetite for bullish bets over bearish.

This positive price action is being stunted in today's session, though, with SINA following the broad markets into the red. At last check, the stock was down 0.5% to linger near $54.75. However, the equity's Relative Strength Index (RSI) of 69 is teetering near overbought territory, suggesting a near-term pullback may have been in the cards.